|  |  | Overview
The previous chapter, "VLANs," provided an introduction to virtual LANs (VLANs) and switched internetworking, compared traditional shared local-area network (LAN) configurations with switched LAN configurations, and discussed the benefits of using a switched VLAN architecture. Despite improvements in equipment performance and media capabilities, network design is becoming more difficult. The trend is toward increasingly complex environments involving multiple media and interconnection to networks outside any single organization's controlled LAN. Keeping all the many factors in mind is important because carefully designing networks can reduce the hardships associated with growth as a networking environment evolves. One of the most critical steps to ensure a fast and stable network is the design of the network. If a network is not designed properly, many unforeseen problems can arise, and network growth can be jeopardized. This design process is truly an in-depth process. This chapter provides an overview of the LAN design process. In addition, LAN design goals, network design issues, network design methodology, and the development of LAN topologies are covered in this chapter.
| Threaded Case Study
Washington Project: Designing the Network

In this chapter, you will begin the process of designing the LAN at your specific site within Washington School District WAN. As concepts and requirements are introduced, you will be able to apply them in your network design. You will need to make sure to address the following requirements:

- The LAN is meant to serve different "workgroups" of staff members and students. This logical division will require the use of VLANs and will be a major design decision. For example, VLANs should be used to secure the administrators' machines from the students' machines.
- Access to the Internet from any site in the school district, via the District WAN, is also an integral part of this implementation.
- A series of servers is needed to facilitate online automations of all the district's administrative functions and many of the curricular functions.

- Because this network implementation must be functional for a minimum of 7-10 years, all design considerations should include at least 100x (times) growth in the LAN throughput, 2x (times) growth in WAN throughput, and 10x (times) growth in the Internet connection throughput.
- A minimum of 1.0 Mbps to any host computer in the network and 100 Mbps to any server host in the network is required.
- Only two routed protocols may be implemented in the network: TCP/IP and Novell IPX.